1. Field of the Invention
This invention relates to an imaging paper capable of producing a three dimensional visible image in response to stimuli imparted thereto and more particularly to an imaging paper which will expand in accordance with a signal imparted thereto in the form of energy.
2. Description of Related Art
U.S. Pat. No. 3,293,114 issued Dec. 20, 1966 discloses papers useful in packaging, printing, preparation of containers and the like wherein hollow expanded spherical particles are incorporated into the paper pulp by admixture with the wet pulp prior to deposition on the screen. These papers demonstrate increase stiffness and increase caliper.
U.S. Pat. No. 3,556,934 represents a method of making papers similar to that described in U.S. Pat. No. 3,293,114, mentioned above, with the exception that this patent teaches the incorporation of the microspheres in an unexpanded state to the aqueous suspension and during the drying of the paper subjecting it to temperatures sufficient to cause the particles to expand within the paper sheet.
U.S. Pat. No. 3,779,951 issued Dec. 18, 1973 relates to an improved method for the expansion of expandable microspheres in the presence of water.
U.S. Pat. No. 3,941,634 issued Mar. 2, 1976 discloses a method for the preparation of paper containing plastic particles by forming two-spaced apart dewatered webs of cellulose fibers introducing expandable thermoplastic beads between the dewatered webs pressing the spaced apart partially dewatered webs together and subjecting this product to heat to at least partially dry the fibers and at least expand a portion of the beads.
U.S. Pat. No. 4,133,688 issued Jan. 9, 1979 discloses a photographic paper coated with a polyolefin on both sides wherein in the preparation of the paper, either non-inflated microspheres which are subsequently inflated during the drying of the paper or inflated microspheres are added to the pulp during preparation of the paper.
U.S. Pat. No. 4,268,615 issued May 19, 1981 relates to a method of producing a relief by forming a layer of a pattern on the surface of a sheet made of a material having the property of increasing in volume when heated, the pattern being made of the material having a stronger ability to absorb light than the aforesaid material, and then radiating a strong light uniformly on the entire surface of the sheet to selectively heat the portion of the sheet adjacent the undersurface of the pattern layer whereby the pattern layer is raised from the sheet surface. The sheet is prepared by mixing microcapsules and a binder such as vinyl acetate polymers.